Precancerous polyps were induced with 21/54 (38.9%) of the isolates (Fig. 3b–c), eight (14.8%) of which were ST1, wild-type ST3 gave a weak reaction in 9/17 (16.8%) of the isolates (two did not induce polyps), the ST3 mutant with weak staining was detected in 2 (5%) of the isolates and the polyp inducer, and heterozygous ST3 gave a weak reaction in four (7.4%) of the isolates (one had no polyps). The gene discussed is MMP11; the disease is polyp.